1. Field of the Invention
The present invention relates to a method and apparatus for image forming, and more particularly to a method and apparatus for image forming capable of effectively recycling an image forming unit.
2. Discussion of the Background Art
In a background image forming apparatus, a toner cartridge or a process cartridge is detachably provided in the background image forming apparatus as an image forming unit, and includes a nonvolatile memory which stores lifetime information such as guarantee information and operation information of the toner cartridge. In the background image forming apparatus, the nonvolatile memory stores the guarantee information of the process cartridge obtained by conversion into the number of rotations of a photoconductor, the number of recording operations of a transfer member, and/or the number of pixels. The guarantee information of the process cartridge is compared with the actual number of rotations of the photoconductor, the actual number of recording operations of the transfer member, or the number of pixels. The lifetime of the process cartridge is determined based on a result of the comparison, and a need for replacement of the process cartridge is informed. Further, guarantee information (e.g., information of a limit number of reproduction operations) of each of individual replaceable component or device (hereinafter referred to as replaceable members) included in the process cartridge is determined based on such factors as the number of replacements of the photoconductor, and the guarantee information is stored in the nonvolatile memory. The guarantee information of the replaceable members is read in a reproduction operation of the process cartridge to find a component or device which is worn. The component may then be replaced before failure.
However, in the background process cartridge, when the photoconductor is detected to be worn out and replaced with a new one, such components as a charging device and a cleaning device attached around the photoconductor need to be detached from a housing of the process cartridge, even though the components are not yet at the end of their respective lives. That is, in the background process cartridge, when one of the replaceable members included in the process cartridge is detected to be at the end of its life and is replaced, other replaceable members need to be detached from the housing of the process cartridge, even though the replaceable members are not yet at the end of their lives. Therefore, it takes a relatively long time to replace the replaceable members, and a replacement operation is troublesome.
Further, the lifetime of the background process cartridge attached to the image forming apparatus is detected based on the guarantee information of the process cartridge obtained by conversion into the number of rotations of the photoconductor. It is in the reproduction operation of the process cartridge that whether the replaceable members in the process cartridge are at the end of their lives and thus need to be replaced is determined. Therefore, in the background process cartridge, even if any one of the replaceable members in the process cartridge is at the end of its life, the replaceable member continues to be used unless the process cartridge is detected to be at the end of its lifetime. As a result, an obtained image and other components and devices may deteriorate because the replaceable member is at the end of its life.